Hi and welcome to our little MS community, I'm sorry for your troubles and hope we can offer you some help and direction.
Children of any age who become the carer of a parent, can unconsciously switch the parent - child relationship in their mind. They have a high amount of responsibility, concern and interaction with their parent, than a normal child would. If the parent is extremely dependant (physical & emotionally) they too can unconsciously switch the parent - child relationship and it can work well when both parties are on the same page.
Problems arise, when either one has expectations that are not being met by the other, eg the child may have expectations of automatic compliance of their authority, the parent may have expectations of care from a child who wouldn't choose to be a carer etc etc.
There are infinite reasons for things to go wrong in any relationship, the only thing anyone has control over is them selves, so if you really need something to change in a relationship, i'd advice anyone to first look at their own behaviour to see if there is anything, they could be 'unknowingly' doing or saying that could be attributing to the situation. Ask your self if you and he need third party help to sort out the underlying problem(s), counselling might benefit you both, and sometimes just talking over a cup of coffee about each others concerns can actually trigger changes.
Cheers........JJ
Monica,
So sorry to hear your son is this way - I don't know the history of your relationship and his background. That could have a lot to do with his wanting to argue with you. You sound desperate, though, and that concerns me. If you feel threatened in any way, please let your doctors know. Or if you have a case worker to help with your social services, you could start there. NMSS has people you can call day or night to talk and you could also talk to them and discuss your options.
I'm so sorry you feel this additional stress in your daily routine.